The invention relates to towing apparatus for vehicles, and more particularly to a tow pin apparatus for large trucks wherein upper and side access to the space behind the front bumper is blocked.
During their assembly in a manfacturing plant, and later in service, many large trucks often must be towed from one place to another. It is usually not desirable to have a permanently installed tow member. It is, instead, preferred to have a removable tow pin.
Therefore, trucks have often included front towbar receiving assemblies wherein a pin for engagement through the eye of a towbar is inserted from above into a retaining assembly behind the front bumper, with the towbar eye received through an opening in the bumper directly in front of the pin-receiving assembly. Thus, the weight of the pin, which is generally quite large in diameter, is depended upon to retain the pin in place. Often two such pins and receiving assemblies have been provided, for engagement with a towbar having two arms. However, the double towbar pins, each of which was usually associated with one side rail or frame member of the truck, would tend to shift the load from one side rail to the other, often tending to overload a single rail.
In certain trucks access to the space behind the front bumper is blocked from above by a radiator assembly or other apparatus positioned closed to the top of the bumper and in generally flush relationship with the bumper. This is particularly true to certain models of cab-over-engine type trucks. Insertion of the pin horizontally from one side of the pin-retaining assembly is impractical, because it would have to be done blindly by reaching up behind the bumper from below and also because side access may be blocked by structural members retaining the bumper to the frame or by accessories such as fog lamps or parking lights which are often positioned in the front bumper.
One solution to the above problem has been the provision of an outwardly swingable housing in the front bumper of a truck, normally retained behind and flush with the bumper but outwardly swingable to enable a towbar pin to be vertically inserted into the housing from above, through a towbar eye. While this swing-out type apparatus provides a workable towing assembly, its high cost prevents it from being commercially acceptable. SUMMARY OF THE INVENTION
The present invention provides an efficient solution to the problem of towbar pin emplacement without complex or costly apparatus. The towbar receiving assembly of the invention includes a single central opening in the truck bumper with a fixed tow eye box connected to the inside of the bumper directly behind the opening. Upper and lower plates of the tow eye box have vertically aligned openings for receiving a single generally dowel-shaped towbar pin inserted from below. The upper end of the pin is provided with at least one, and preferably two, radially outwardly extending tabs which in proper orientation of the pin fit through complementarily-shaped slots in the periphery of the upper plate opening. The lower plate opening, which must first receive the upper end of the pin during installation, may also be sized to fit closely over the pin end with slots similar to the upper opening, thereby establishing the proper orientation of the pin as it is passed through the lower opening. On the top of the upper plate is a riser or boss at the location of each slot, so that as the pin tabs pass upwardly through the slots and clear the bosses, the pin may be rotated approximately 90.degree. so that the pin drops down to a locked-in position in which the tabs are resting on the upper plate rotationally spaced from the boss areas. On the bottom end of the towbar pin, a handle may be provided for helping to orient the pin rotationally for installation and also for limiting the upward travel of the pin in the tow eye box, by a radial projection on the handle.
The tow eye box and the central bumper area are preferably both braced to the side rails of the truck frame by a pair of braces, each of which extends from one side of the tow eye box rearwardly at an oblique angle to the bumper to a connection with a side rail. Thus, the centrally positioned tow pin allows the tow load to be equally distributed between the side rails.
Accordingly, it is among the objects of the invention to provide, especially for large trucks which do not allow access to the space behind the front bumper from above, a towbar-receiving assembly wherein the towbar pin is quickly and easily inserted from below the bumper and securely locked in place after installation. This and other objects of the invention will become apparent from the following description taken in conjunction with the accompanying drawings.